The Animal Core C will perform a variety of services for individual projects related to the utilization and evaluation of bleomycin-treated mice. The Specific Aims of the Animal Core include: 1. Providing a standardized model of bleomycin-treated mice to other components of the SCOR program. The lungs will be assessed histologically and biochemically for evidence of fibrosis. The Core will administer potential therapeutic agents and assess their activity in this murine model of pulmonary fibrosis. 2. Developing and/or maintaining transgenic mice strains utilized in the various components of the SCOR program. The Core will perform a variety of specialized functions on bleomycin- treated wild-type and transgenic animals for individual projects within the program. These procedures include the placement of osmotic pumps, RNA isolation and Northern blot analysis of lung tissue, in situ hybridization, and immunohistochemistry. The goal of the Core is to provide an easily accessible animal model to explore new ideas in the pathogenesis and treatment of pulmonary fibrosis.